Conventionally, due to the development of a virtualization technology, plural virtual servers have been built on one physical host computer, a configuration in which the images of the virtual servers and usage data are stored in a storage device has been widely spread, and further data of one or more virtual servers has been concentrated on one logical volume of the storage device. However, in this data concentration configuration, when the local copy function and remote copy function of the storage device are used, a copy unit is composed of plural virtual servers, so that virtual servers that are not target virtual servers and included in the copy unit become wasteful costs.
To cope with the above problem, Patent Literature 1 proposes Conglomerate LUN Structure, in which plural logical volumes of a storage device are held together into plural logical groups (LUN Conglomerate), a logical path is set in a representative logical volume (ALU: Administrative Logical Unit, PE (Protocol End Point) in Patent Literature 1) of each logical group; an I/O (Input/Output) command issued from a host computer includes an identifier of a logical volume (SLU: Subsidiary Logical Unit, vvol (virtual volume) in Patent Literature 1) other than the ALU to which the logical path belongs in each logical group; and the storage device delivers the relevant I/O processing to the SLU specified by the reception command. With the use of the above structure, one or more SLUs are assigned to one virtual server on the host computer, so that it becomes possible to assign an appropriate number of logical volumes of the storage device to each virtual server.
In addition, Patent Literature 2 discloses a technology in which a control device that controls the logical resources of a storage system includes: a virtual resource preparation unit that prepares virtual resources that are virtual logical resources; a real resource assignment unit that assigns real resources, which are substantial logical resources, to the above-described prepared virtual resources; and a data duplication control unit that duplicates data in a logical volume as duplicate data in a logical volume in a different storage system. Furthermore, in this technology, the identification of the virtual resource of the duplication source logical volume and that of the duplication destination logical volume are set the same, so that a higher-level host computer recognizes the two logical volumes as one logical volume. Therefore, Patent Literature 2 also discloses in this technology that the control device that controls the logical resources of a storage system makes an I/O command transmitted from the host computer to a logical volume in the storage system transferred to a logical volume in another storage systems.